I. Field
The subject invention relates generally to data communications, and more particularly to systems and methods for selecting an initial pilot frequency for a wireless communication system.
II. Background
Communicating has always been of paramount importance to humankind. Long before the advent of modern technologies, sound waves were utilized to convey information with the human voice. However, this type of communication was severely limited by the power of the human lungs. To overcome this problem, sound wave producing devices were used in place of the human voice, such as drums, to increase communication distances. However, when distances between parties were too great for the sound waves to be interpreted by the human ear, communication was lost. Thus, great strides were made to overcome this limitation through advances in technology. In one solution, sound waves were converted to electricity which was, in turn, transmitted through wires to a final destination where the electricity was then converted back into sound waves. The telephone is one such example of this technology.
Despite the fact that this solution greatly increased communication distances, it also introduced an additional associated problem, namely the requirement of wiring to transport the electrical signals between communication points. The wiring is often costly and requires great quantities to cover immense distances and to handle increased user numbers. Technology attempted to resolve some of the issues through the development of fiber optic cable which can carry light impulses instead of electrical currents. This drastically reduces the number of wires required to transport the same amount of communications. However, fiber optics come with an increased price and substantially increased costs for repairs and skill levels to maintain a fiber optic network.
Although one first thinks of ‘communicating’ being a human type of interaction, the dawning of the computer age also brought with it the necessity to link computers together. Thus, communication networks are not only required to carry the human voice, but also information that consists of digitized data (data converted to ones and zeros). In fact, some technologies even digitize the human voice to more efficiently transport it over great distances. This demand has greatly increased the workload of typical communication networks and driven a substantial increase in the number of wires or cables.
One seemingly obvious way to overcome the problem of vast, wired communication networks is to do away with the wires and utilize a “wireless” communication system. Although the solution seems easy enough, developing wireless communications is typically a complex issue. Early wireless communication techniques, such as the radio, enabled remote areas to receive broadcasts from distant places. This “one-way” type of communicating is a great means to disseminate information such as announcements and news. However, it is frequently desirable to have two-way communications or even greater than two-way communications. In other words, it is desirable to have a ‘conversation’ between two or more parties, whether they are human beings or electronic devices. This greatly increases the complexity of the wireless signals required to effectively communicate.
With the introduction of wireless technology for the telephone, the sheer numbers of parties desiring to communicate wirelessly have increased substantially. The wireless telephones developed into multifunctional devices that not only functioned to relay voice communications, but data as well. Some devices have also incorporated interfaces to the Internet to allow users to browse the World Wide Web and even download/upload files. Thus, the devices have been transformed from a simple voice device to a “multimedia” device that enables users to receive/transmit not only sound, but also images/video as well. All of these additional types of media have tremendously increased the demand for communication networks that support these media services. The freedom to be ‘connected’ wherever a person or device happens to be located is extremely attractive and will continue to drive future increases in network demand.
Thus, the ‘airwaves’ in which wireless signals are sent become increasingly crowded. Complex signals are employed to utilize signal frequencies to their fullest extent. However, due to the sheer numbers of communicating entities, it is often not enough to prevent ‘collisions’ of signals. When collisions occur, a receiving entity may not be able to properly interpret the signal and may lose information associated with that signal. This drastically reduces the efficiency of a communication network, requiring multiple sends of the information before it can be properly received. In the worst case, the data may be totally lost if it cannot be resent. If a network has hundreds or even thousands of users, the probability of a signal collision increases substantially. The demand for wireless communications is not decreasing. Therefore, it is reasonable to assume that signal collisions will also increase, degrading the usefulness of existing technology. A communication system that can avoid this type of data corruption will be able to provide increased reliability and efficiency to its users.